Chronic stress exposure is hypothesized to increase the risk for developing a mental or physical disease, which can be summarized as an overall increased vulnerability to adverse health conditions. This thesis shows one potential pathway of stress exposure entering the body via activation of the hypothalamus pituitary adrenal (HPA) axis and the interaction between HPA axis and immune activation. Chronic stress caused by work overload or the experience of stressful life events was associated with altered levels of cortisol, the main effector hormone of the HPA axis. Further, chronic stress was shown to effect the distribution of neutrophils, a leukocyte subtype known for its defence properties as well as for its side effects of tissue damage. Additional analyses support a theory that HPA axis and immune cells work in synergy to adapt the organism to chronic stress exposure and therefore represent one pathway how stress can cause altered immune defence toward an increased vulnerability to disease.

Humans are extraordinary prosocial beings. No other Great Ape species invests a comparable amount of time and resources into building, maintaining, and repairing social relationships. The degree to which small-scale communities and large-scale societies embrace the human capacity for prosociality and capitalise on human-unique forms of cooperation is variable. The cross-cultural constant, however, is that each individual child undergoes a critical period of prosocial development in the first four years of life. During this period children’s emotions undergo a culture-specific transformation through children’s interactions with adults, siblings, and same-age peers. Studying how emotions shape young children’s social interactions, how they allow children to maintain and repair social relationships, is the developmental psychologist’s study of the psychological origins of human prosociality. This thesis is about studying examples of such so-called prosocial emotions. The main question of the current thesis is: How do emotions regulate children’s social inter- actions and relationships in early ontogeny? Addressing this question requires the assessment of both the internal mechanisms (attention and physiological arousal) as well as the expression (in behaviour or body language) of emotions in young children’s social interactions. At first, I provide a theoretical basis for studying the regulatory function of prosocial emotions in the first four years of children’s development. I suggest that children’s developing prosociality progresses through two distinct phases, one which shapes their attention and physiological arousal to others’ needs in the first two years of life, and subsequently a second phase during which children’s prosocial behaviour emerges and is increasingly regulated by emotions. In contrast to previous work, such a study of emotions as underlying early prosocial development requires broadening the suite of methods through which emotions are objectively measurable and interpretable. The first research aim was to study the development of children’s attention and arousal in response to others’ needs. We found that prosocial attention is a stable phenomenon from toddlerhood through school-age. In both a western and non-western culture, children anticipated how others are best helped. In a clinical comparison study, we found that this anticipatory response was blunted in children with an autism spectrum diagnosis. Young children’s prosocial orientation was not limited to helping contexts but encompassed other domains. Toddlers understood others’ desires and anticipated how those were best met. We further found that two-year toddlers were attentive to same-age peers’ needs and helped a same-age peer in sim- ilar ways and to a similar degree as has been previously reported in studies with child-adult interactions. We further found that toddlers’ attention to others’ needs was not contingent on explicit requests for help. Rather toddlers helped an adult even if helping was anonymous suggesting that toddlers did not help to interact with a competent adult partner. Finally, in a comparative study, we found chimpanzees’ underlying motivation to provide help to be different from that previously documented in young children. Chimpanzees were fastest to complete an action if this resulted in a conspecific’s need being fulfilled but, in contrast to young children, chimpanzees were motivated to carry out the behaviour themselves (which was not the case in non-helping control scenarios). Together, this indicates that a young chil- dren’s prosocial orientation develops during and persists beyond the first two years of life, thus laying the foundation for children’s prosocial behaviour. The second research aim was to study how children’s attention to others’ needs relates to their actual prosocial behaviour. In a first, comparative, study we found that young children regulated their prosocial behaviour more than chimpanzees. Both 3-year-old children and chimpanzees helped others, but children were more strongly motivated to help paternalistically by correcting dysfunctional requests for help that did not align with the requester’s actual need. The implication of these findings is that chimpanzees’ helping is more motivated by concerns to ’get credit’ and comply with others’ request for help whereas children’s helping is based on a, sometimes even paternalistic, concern to see others being helped. In a separate series of studies we developed experimental paradigms that allowed us to mea- sure the underlying emotions through changes in both internal arousal as well as overt body expressions. We found that changes in children’s physiological arousal were predictive of their subsequent helping behaviour. We further studied the function of guilt and gratitude in regulating two- and three-year-olds’ prosocial behaviour. Children’s intrinsic motivation to help an adult changed when they had accidentally caused the adult harm (guilt) or when the adult had previously helped them (gratitude). Specifically, guilt- and gratitude-provoking situations motivated young children to actively provide help. In contrast, and replicating previous work, under conditions without invoked guilt or gratitude, children’s motivation was to see that individual being helped (irrespective of whether they themselves or another adult provided the help). In a separate study we investigated children’s positive emotions, expressed in elevated upper-body posture, resulting from their successful helping behaviour. Children at the age of two years showed a similarly elevated body posture after completing a goal for themselves and after completing an adult’s goal whereas no such elevation was observed when children’s actions did not benefit anyone. Together these findings suggest that emotions invoked in their interactions with others in turn influence children’s motivation to interact, thus serving a regulatory function to repair (guilt) and maintain (gratitude) children’s social relationships. This successful navigation of the social world may contribute to children’s own emotional well-being. In sum, the current thesis explored the developmental origins of prosociality focusing on prosocial emotions that allow already young children to build and maintain functional relationships with adults and peers. The first four years of life give rise to prosocial emotions that critically shape children’s social interactions toward cooperative ends. Together, the re- search presented here adds to our knowledge of the deep ontogenetic roots of human-unique prosociality.:1 Executive summary 1 2 Introduction and background 3 2.1 Children’s prosocial attention and interactions.................... 6 2.2 The regulatory social function of children’s emotions . . . . . . . . . . . . . . . . 8 2.2.1 Children’s emotional response to seeing others needing help . . . . . . . 8 2.2.2 Children’s emotional response to seeing others being helped . . . . . . . 9 3 Theoretical framework and research programs 11 3.1 Revealing the foundation of human prosociality (Theoretical paper 1) . . . . . 11 3.1.1 Precursors and mechanisms........................... 12 3.1.2 Social groups & interaction partners...................... 13 3.1.3 The self in social relationships ......................... 13 3.1.4 The long reach of early development ..................... 14 3.2 ResearchPrograms .................................... 15 3.2.1 Prosocial attention and interactions ...................... 16 3.2.2 The regulatory social function of emotions . . . . . . . . . . . . . . . . . . 17 4 Empirical studies 21 4.1 The development of prosocial attention across two cultures (Study 1) . . . . . . 21 4.1.1 Abstract ...................................... 21 4.1.2 Introduction.................................... 21 4.1.3 Materials and methods.............................. 24 4.1.4 DataAnalysis................................... 26 4.1.5 Results....................................... 28 4.1.6 Discussion..................................... 31 4.2 Prosocial attention in children with an autism spectrum diagnosis (Study 2) . . 35 4.2.1 Abstract ...................................... 35 4.2.2 Introduction.................................... 35 4.2.3 Methods...................................... 38 4.2.4 Data analysis ................................... 40 4.2.5 Results....................................... 44 4.2.6 Discussion..................................... 46 4.3 Desire understanding in 2-year-old children: An eye-tracking study (Study 3) . 50 4.3.1 Abstract ...................................... 50 4.3.2 Introduction.................................... 50 4.3.3 Methods...................................... 53 4.3.4 Results....................................... 57 4.3.5 Discussion..................................... 61 4.4 Toddlers help anonymously (Study4)......................... 65 4.4.1 Abstract ...................................... 65 4.4.2 Introduction.................................... 65 4.4.3 Study1....................................... 66 4.4.4 Study1: Methods................................. 66 4.4.5 Study1: Results.................................. 70 4.4.6 Study1: Discussion................................ 70 4.4.7 Study2....................................... 72 4.4.8 Study2: Method ................................. 72 4.4.9 Study2: Results.................................. 74 4.4.10 General discussion ................................ 75 4.5 Toddlers help a peer (Study5) ............................. 79 4.5.1 Abstract ...................................... 79 4.5.2 Introduction.................................... 79 4.5.3 Method....................................... 81 4.5.4 Results....................................... 86 4.5.5 Discussion..................................... 89 4.6 Chimpanzees are motivated to help others - and to get credit (Study 6) . . . . . 93 4.6.1 Abstract ...................................... 93 4.6.2 Introduction.................................... 93 4.6.3 Study1....................................... 95 4.6.4 Results.......................................100 4.6.5 Study2.......................................102 4.6.6 Results.......................................103 4.6.7 General discussion ................................104 4.7 Chimpanzees comply with requests; Children fulfil others’ needs (Study 7) . . . 106 4.7.1 Abstract ......................................106 4.7.2 Introduction....................................106 4.7.3 General method..................................109 4.7.4 Study1.......................................111 4.7.5 Results.......................................115 4.7.6 Study2.......................................116 4.7.7 Results.......................................119 4.7.8 General discussion ................................119 4.8 Young children’s physiological arousal and their motivation to help (Study 8) . 123 4.8.1 Abstract ......................................123 4.8.2 Introduction....................................123 4.8.3 Methods......................................126 4.8.4 Data analysis ...................................128 4.8.5 Results.......................................130 4.8.6 Discussion.....................................131 4.9 Children’s intrinsic motivation to reconcile after accidental harm (Study 9) . . . 135 4.9.1 Abstract ......................................135 4.9.2 Introduction....................................135 4.9.3 General method..................................137 4.9.4 Study1.......................................142 4.9.5 Study1: Results and discussion ........................145 4.9.6 Study2.......................................146 4.9.7 Study2: Results..................................148 4.9.8 General discussion ................................149 4.10 Toddlers’ intrinsic motivation to return help to their benefactor (Study 10) . . . 152 4.10.1 Abstract ......................................152 4.10.2 Introduction....................................152 4.10.3 Study1:Methods.................................155 4.10.4 Study1:Results..................................161 4.10.5 Study1:Discussion................................163 4.10.6 Study2:Methods.................................164 4.10.7 General discussion ................................167 4.10.8 Conclusion.....................................170 4.11 The fulfillment of others’ needs elevates children’s body posture (Study 11) . . . 171 4.11.1 Abstract ......................................171 4.11.2 Introduction....................................171 4.11.3 Validation study .................................173 4.11.4 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175 4.11.5 Study 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175 4.11.6 Study1:Method .................................176 4.11.7 Study1:Results..................................181 4.11.8 Study1:Discussion................................183 4.11.9 Study 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184 4.11.10 Study2:Method .................................185 4.11.11 Study 2: Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188 4.11.12 General discussion ................................189 5 Integrative discussion and theoretical perspectives 193 5.1 Children’s prosocial attention and interactions . . . . . . . . . . . . . . . . . . . .194 5.1.1 Summary & conclusions.............................194 5.1.2 Future directions .................................195 5.2 Prosocial arousal in children (Theoretical paper 2) . . . . . . . . . . . . . . . .200 5.2.1 Abstract ......................................200 5.2.2 Introduction....................................200 5.2.3 The phenomenon and the debate........................201 5.2.4 Measuring prosocial arousal ..........................202 5.2.5 Children’s prosocial arousal and intrinsic motivation to help . . . . . . . 204 5.2.6 Looking ahead ..................................205 5.2.7 Conclusion.....................................207 5.3 The regulatory social function of children’s emotions . . . . . . . . . . . . . . . .207 5.3.1 Summary & conclusions.............................207 5.3.2 Future directions .................................208 5.4 The development of prosocial emotions (Theoretical paper 3) . . . . . . . . . . 211 5.4.1 Abstract ......................................211 5.4.2 Introduction....................................211 5.4.3 The prosocial functions of emotions......................212 5.4.4 General discussion and future directions . . . . . . . . . . . . . . . . . . .220 6 Bibliography 227 7 Declaration of originality 255 8 Contribution statement 257

The 21st century world is characterized by globalization, optimization, high performance demands, and continuous acceleration of processes. Not surprisingly, stress has steadily become more prevalent over the past years and has become a permanent challenge for many of us. Still we are always expected to perform at our best, and an impairment of cognitive performance can be devastating, particularly in the professional world. This ubiquity in daily life of chronic stress, cognitive demands, and their potential interactions was the motivation for this dissertation. Among cognitive processes executive functioning (EF) are of particular interest, as they represent set of fundamental cognitive abilities for mastering daily life. More precisely, EF is described as higher-order cognitive processes that control and coordinate complex cognitive tasks (Diamond, 2013; Miyake et al., 2000). The primary aim of this dissertation was to investigate the interplay between chronic stress and EF in detail. A three-year longitudinal cohort, the StressCog cohort, was established for this purpose. In order to understand the longitudinal interplay between chronic stress and EF, methodological foundations and cross-sectional matters had to be investigated first. As a result, this dissertation encompasses the following three studies: With classical laboratory designs, the estimation of generalizable and robust effects on the relationship between chronic stress and EF is impaired. Therefore, the StressCog study was set up to make use of internet-based data assessment within domestic environments. Study 1 addressed the feasibility of internet-based response time data, including the common concern that internet-based response time data collected in domestic environments is subject to increased data variability (Chetverikov & Upravitelev, 2016; Reips, 2002). To this end, performance measures collected in the laboratory were compared with measures collected in domestic environments. We found that a setting-related difference in the variability of conventional performance measures (i.e., response times and error rates), as well as diffusion model-based measures is only of small size. An overall increase of variance of approximately 5% was visible in domestic environments. However, as internet-based assessments allow for the recruitment of larger sample sizes (Reips, 2002) the loss of static power can be easily compensated. Therefore, the findings of Study 1 support the use of internet-based cognitive data collection in domestic environments. This formed a valuable basis regarding the collection and interpretation of the StressCog data used in Study 2 and Study 3. In order to get a broad picture of chronic stress the StressCog study aimed for multimethod assessment. The subjective (i.e., perceived) extent of chronic stress and conceptually related constructs were assessed by multiple self-reported measures. The objective (i.e., physiological) extent of chronic stress was assessed via hair cortisol concentration, which has been established as a widely accepted biological marker of chronic stress (E. Russell et al., 2012; Stalder & Kirschbaum, 2012). Surprisingly, however, multiple studies have shown that hair cortisol concentration is, at best, only weakly correlated with subjective chronic stress (Stalder et al., 2017; Staufenbiel et al., 2013; Weckesser et al., 2019). This lack of psychoendocrine covariance was addressed in Study 2 by investigating the construct validity of commonly used chronic stress instruments. A multidimensional item response theory approach was applied in order to display the overlap between items of commonly used measures of chronic stress, depressiveness, and neuroticism. A common latent scale covered the major amount of variance (40% to 48%). It appeared that the overlap of content is mainly based on fatigue, which is a core symptom of depressiveness. Similar to previously reported findings, the common latent scale displayed only a weak association with hair cortisol concentration. It can therefore be argued that items of self-reported chronic stress do not reflect the physiological (i.e., endocrine) aspect of chronic stress to a satisfactory extent. Thus, the results of Study 2 were a valuable basis for the interpretation of chronic stress data in Study 3. In Study 3, we investigated the cross-sectional association between chronic stress and EF. The study made use of data from the baseline assessment of the StressCog cohort (N = 514). Using structural equation modelling, we found no evidence for a meaningful association between chronic stress (i.e., self-reported measures and hair cortisol concentration) and a common latent EF factor. The results found in Study 3 were further supported by unpublished longitudinal StressCog data and analyses making use of diffusion model performance measures. Considering the mainstream of existing findings, which suggests chronic stress to be negatively associated with EF (e.g., Deligkaris et al., 2014; Sandi, 2013), an absence of an association between chronic stress and EF seems surprising. However, other existing findings support this perspective (Castaneda et al., 2011a; McLennan et al., 2016). Beyond this, the results of Study 1 and 2 help to explain why a lack of an association between chronic stress and EF is quite plausible. As within traditional, laboratory-based settings a recruitment of larger samples sizes is difficult and costly, most existing studies lack large, representative samples. In consequence, many findings are based on narrow sample characteristics. Supported by the findings of Study 1, the StressCog study made use of internet-based data collection, which led to the establishment of one the largest, population-based cohorts in the field. Thus, the results presented in this dissertation can be seen as much more robust and representative than many other studies that suggest opposing results. The findings of Study 2 allow for the assumption that many studies in the field make use of questionable self-report instruments and that subjective (i.e., self-reported) measures of chronic stress are only weakly related to objective (i.e., HCC) measures. In consequence, results always depend on the operationalization of the chronic stress measures being used. Caution is advised when comparing opposing results of different measures. With regard to our daily life demands, it may appear quite promising that no association between chronic stress and EF was found in this dissertation. However, these results should not be misunderstood. It has been demonstrated countless times that chronic stress can severely affect the human organism, causing various negative effects that go far beyond a possible impairment of cognitive abilities. Knowing that chronic stress can impair EF under certain circumstances leads to the central question of what conditions make stress toxic. In order to answer this question further systematic research is needed, in which representative samples and experimental study designs will be of crucial help. As long as these questions are not satisfactorily clarified, it seems best to deal with the challenges of chronic stress in a conscious and responsible manner.

In der vorliegenden Arbeit wurde einem Phänomen nachgegangen, das bislang nur wenig wissenschaftliche Beachtung erfahren hat: der Stigmatisierung von leistungsstarken SchülerInnen als Streber. Da sich bislang kaum Forschung mit der Streber-Etikettierung beschäftigt hat, wurde in der vorliegenden Arbeit versucht, anhand quantitativer Studien ein umfassendes Bild von der Etikettierung, ihrer Prozesse und ihrer Konsequenzen zu erfassen. In diesem Rahmen wurde folgenden Fragen nachgegangen: 1) Welche individuellen Faktoren sagen die Etikettierung als Streber und die Stigmatisierung anderer SchülerInnen als Streber vorher? 2) Welche Prozesse liegen der Stigmatisierung als Streber zugrunde? 3) Mit welchen Konsequenzen geht die Stigmatisierung einher? 4) Welche Faktoren tragen zur sozialen Akzeptanz von SchülerInnen mit herausragenden schulischen Leistungen bei? Die vorliegenden Befunde deuten darauf hin, dass es sich dabei um ein relevantes Phänomen handelt, welches mit individuellen Faktoren nebst schulischen Leistungen verbunden ist, durch den Klassenkontext determiniert wird und zudem mit aversiven Konsequenzen für die Betroffenen einhergeht. Neben dieser eher negativen Konnotation zeigen die Befunde aber auch auf, dass es Möglichkeiten zum Umgang und zur Lösung gibt. Mit der vorliegenden Arbeit konnte ein wichtiger Schritt zur Schließung einer Forschungslücke getan werden. Nichtsdestoweniger zeigen die Befunde auch, dass für eine allumfassende Erklärung des Phänomens Streber weitere Forschung dringend benötigt wird.

There is a large body of empirical evidence that nature delivers benefits to people. In the face of progressive urbanisation, urban nature and its design are becoming increasingly important. At the same time, climate change endangers biological diversity and consequently ecosystem functioning. Thus, for urban landscape planners who consider both ecosystem health and residential well-being, it is attractive to simultaneously increase plant diversity and the recreational value of urban nature. The present dissertation investigates the role of tree parameters for perception, preference, and recreation and elucidates how findings can contribute to human and ecosystem health in cities. In a first study, the following tree parameters were identified to be relevant to perception: Conifers versus deciduous trees, crown height to crown width ratio, crown size to trunk height ratio, and crown density. These results add to previous studies, as they are based on more realistic-looking images. Furthermore, the parameters are metric, were generated by study participants and represent a hierarchy. Two further studies demonstrated that the greater the crown relative to trunk height, the more pleasant and the more beautiful a tree is perceived and the denser a crown, the heavier and the more rugged a tree is perceived. Both parameters predict tree preference. This is consistent with theories and previous findings on landscape perception and adds more precise parameters for tree preference prediction to the literature. A fourth study revealed no effects of tree characteristics’ diversity in urban green spaces on how fascinating and coherent they are perceived. This suggests that species diversity in green spaces can be increased without reducing restorativeness. The identified tree parameters can be used to select various, similar-looking species to increase both human well-being and ecosystem health. Furthermore, the knowledge on the tree parameters’ semantic meaning can facilitate expert-lay communication. The preferred tree characteristics can be used to increase residential satisfaction. Finally, tree species diversity in urban green spaces can be increased without mitigating the recreational value. / Die positiven Wirkungen von Natur auf den Menschen sind empirisch gut belegt. Angesichts steigender Urbanisierung wird Stadtnatur und ihre Gestaltung wichtiger. Gleichzeitig stellt der Klimawandel eine Bedrohung der biologischen Vielfalt und somit der ökosystemaren Funktionalität dar. Für urbane Landschaftsplanung, welche sowohl die ökosystemare Gesundheit als auch das Wohlbefinden der Stadtbewohner berücksichtigt, ist es daher attraktiv, zugleich die Pflanzenvielfalt und den Erholungswert von Stadtnatur zu erhöhen. Die vorliegende Dissertation untersucht die Rolle von Baumparametern bei der Wahrnehmung, Präferenz und Erholungswirksamkeit und erläutert, wie die Ergebnisse zur Gesundheit von Mensch und Natur in Städten beitragen können. In einer ersten Studie wurden die folgenden Baumparameter als wahrnehmungsrelevant identifiziert: Nadelbäume versus Laubbäume, Verhältnis von Kronenhöhe zu Kronenbreite, Verhältnis von Kronengröße zu Stammlänge und Kronendichte. Diese Ergebnisse ergänzen bisherige Literatur, da sie auf realistischer aussehenden Bildern basieren. Zudem sind die Parameter metrisch, wurden von Probanden generiert und bilden eine Hierarchie ab. Zwei weitere Studien zeigten, dass je größer die Krone im Verhältnis zur Stammlänge desto angenehmer und schöner wird ein Baum wahrgenommen und je dichter die Krone desto schwerer und robuster wird ein Baum empfunden. Beide Parameter sagen die Baumpräferenz vorher. Dies stimmt mit Theorien und bisherigen Studien zur Landschaftswahrnehmung überein und ergänzt die Forschung um präzisere Parameter zur Vorhersage von Baumpräferenz. Eine vierte Studie ergab, dass sich die Vielfalt an Baumeigenschaften in städtischen Grünräumen nicht darauf auswirkt, wie faszinierend und kohärent sie wahrgenommen werden. Dies legt nahe, dass die Artenvielfalt in Grünräumen erhöht werden kann ohne die Erholungswirkung negativ zu beeinflussen. Die Baumparameter können dazu verwendet werden, verschiedene, ähnlich aussehende Arten zur Pflanzung auszuwählen, um das menschliche Wohlbefinden sowie die ökosystemare Gesundheit zu erhöhen. Des Weiteren kann das Wissen um die semantischen Bedeutungen der Baumparameter die Experten-Laien-Kommunikation erleichtern. Beliebte Baummerkmale können dazu herangezogen werden, die Zufriedenheit von Stadtbewohnern zu erhöhen. Schließlich kann die Baumartenvielfalt in städtischen Grünräumen erhöht werden ohne den Erholungswert zu mindern.

Human decision making is closely related to reward processing because many decisions rely to a certain degree on the evaluation of different outcome values. Reward-based decisions can be health-related, for example if someone has to compare the outcome value of the instant reward of smoking a cigarette to that of the long term goal of keeping well and fit. Such comparisons do not only rely on the nominal value of the alternatives but also on devaluation of rewards over time. The value of being healthy at older age might outweigh the value of smoking a cigarette but since the payoff of the health-outcome will be delayed, humans tend to decrease the value of this option. Therefore in this example one might choose the immediate reward of smoking a cigarette. The proclivity to devaluate the value of rewards over time has been widely investigated with experimental intertemporal choice tasks, in which subjects have to choose between smaller sooner rewards and larger later rewards. A stronger individual devaluation proclivity (i.e. discounting rate) has been reported to be related to addiction. Research in neuroeconomics has suggested the competing neurobehavioural decision systems (CNDS) theory, proposing that an imbalance between an executive (cortical prefrontal brain areas) and an impulsive (i.e. subcortical areas, such as ventral striatum (VS), amygdala) system in the brain leads to steeper discounting and a higher risk for addiction. Additionally, temporal discounting has been proposed as a transdisease process, i.e., “a process that occurs across a range of disorders, making findings from one disorder relevant to other disorders” (Bickel, Jarmolowicz, Mueller, Koffarnus, & Gatchalian, 2012, Abstract). Thus, the CNDS theory and temporal discounting might also have implications for other health-related behaviour than substance use. So far many factors have been shown to be associated with higher discount rates: for instance, adolescent age, lower intelligence and nicotine dependence. Further, it has been shown that adolescents are at highest risk to start smoking. On the other hand a higher education level has been shown to be associated to lower rates of smoking. Thus, it seems likely that a higher discount rate might be one reason why adolescents experiment with smoking, why lower education is associated to nicotine addiction and why dependent smokers are not successful in smoking cessation. But relatively little is known about the neural processes behind these variables, which could be also seen as exemplary risk- and protective factors regarding addiction. The 3 studies of the thesis at hand were conducted to extend the knowledge about neural processes associated to age, intelligence and smoking in their relation to intertemporal choice. The task was chosen because of its relevance for addiction and a variety of health-related behaviour. The first study was conducted to explore the neural correlates of age related differences between adolescents at age 14 and young adults during intertemporal choices. Additionally, the roles of discounting and choice consistency were investigated. Although adoles-cents discounted delayed rewards more steeply than adults, neural processing of reward value did not differ between groups, when controlling reward values for the individual discount rates. However, a higher discount rate was related to a lower responsivity in the ventral striatum to delayed rewards, independent of age. Concerning decision making, adolescents exhib-ited a lower consistency of choices and less brain activity in a parietal network than adults (i.e. posterior and inferior parietal regions). Thus, reward value processing might be more sensitive to the discount rate than to chronological age. Lower consistency of intertemporal choices might indicate ongoing maturation of parietal brain areas from adolescence to young adulthood. The second study was conducted to reveal the associations between neural processes of decision making and intelligence in adolescents. The results of study 2 revealed networks in the adolescent brain where brain activity was related to crystallised intelligence as well as to intertemporal choice behaviour. Specifically, during decision processing higher crystallised intelligence as well as more consistent decisions were associated with higher brain activity in the posterior parietal cortex. Processing of delayed rewards was also related to crystallised intelligence, i.e. more intelligent adolescents showed higher brain activation in the anterior cingulate cortex (ACC) and the inferior frontal gyrus (IFG), which was in turn related to a lower discount rate. Additionally, associations between the parental education level and crys-tallised intelligence of the adolescent participants of the study and their discount rate were found, indicating that parental education as an environmental factor could be related to a low-er risk for addiction. This protective effect might be mediated by the offspring’s crystallised intelligence and discount rate which are both related to brain activity in parts of the same brain networks (i.e. the IFG). The third study was done to investigate neural processes of intertemporal decisions in smokers and non-smokers. To test whether the effects of smoking on the discount rate are due to chronic or acute nicotine intake, non-smokers were additionally assessed under acute nico-tine administration. Study 3 revealed that the effects of nicotine on intertemporal choice behaviour were related to chronic intake of nicotine in smokers rather than to acute nicotine ad-ministration in non-smokers. Regarding the neural processes, smokers compared to non-smokers showed lower brain activity in the posterior parietal cortex. Comparable but weaker effects were found under acute nicotine in non-smokers. Although acute nicotine administra-tion altered neural processes, behavioural changes might only occur after repeated nicotine intake. However, the study did not preclude that the differences are predrug characteristics. Altogether the studies revealed overlapping neural correlates of intertemporal choices which are related to the individual age, the discount rate, the choice consistency, the individual intelligence as well as acute and chronic nicotine intake. This might provide an integrative view on how inter-individual differences and behaviour during intertemporal choices are based on common neural correlates which in turn might have implications for the development and the maintenance of addiction. Specifically, hyposensitivity towards delayed rewards in the adolescent ventral striatum, which has also been found in smokers compared to non-smokers, is associated with higher discount rates and higher risk for smoking initiation. In contrast, higher activation in the IFG and the ACC in more intelligent individuals during reward value processing might enhance behavioural inhibition and control and, hence, might prevent nicotine addiction. In line with the CNDS theory responsivity in subcortical brain areas (i.e. impulsive system), such as the VS was related to the risk factor of adolescent age, whereas activity in cortical areas (IFG and ACC) was related to the protective factors of high-er crystallised intelligence. Since there was only one study beside the studies of the current thesis reporting results regarding consistency, one can only speculate about implications for health-related behaviour, such as addiction. Consistency might play a role, especially for cessation success. Thus, the findings that adolescents as well as less intelligent individuals were less consistent might point to a higher risk for maintenance of nicotine addiction. The higher brain activity in a fronto-parietal network, which has been shown in studies 1 and 2 in adults as well as in more intelligent adolescents, was related to higher consistency of choices in both studies. Thus, the finding might be a possible neural correlate for the association between the risk factor of ado-lescent age, the protective factor of higher crystallised intelligence, and more consistent deci-sion making. In conclusion the findings of the current thesis contribute to a better understanding of how inter-individual differences and environmental factors might be accompanied by neural processes which in turn might be related to individual development of addiction. Further the results might extend the CNDS theory regarding neural correlates of exemplary risk and pro-tective factors regarding adolescents’ health behaviour and smoking in adults.

The frequency of social dysfunctions in a general population sample and in different diagnostic groups was investigated by using the Social Interview Schedule (SIS). Based on the results of the general population sample, several of the a priori derived cut-off scores of the SIS were modified. The analysis of the general population sample revealed sex-specific relationships between age and different aspects of social functioning. Especially for younger women significantly more objective social restrictions, were found due to the burden of multiple role responsibilities. With regard to different diagnostic subgroups including patients and mostly untreated cases from the community sample with Affective Disorders and Anxiety Disorders, results indicate that the degree of social impairment and dysfunctions and the degree of satisfaction with different role areas are strongly dependent on type of disorder and on former treatment status. Specific findings are: (1) The highest number of social impairments and dysfunctions were found in cases and patients with affective syndromes and in schizophrenic patients, but not in schizoaffective patients. (2) Management difficulties and dissatisfaction in intimate relationships were primarily found in depressed women. (3) Unlike anxiety patients, anxiety cases, although mostly chronically ill, had significantly less objective impairments and a lower rate of dissatisfaction than depressed cases. The results are discussed with special reference to the possible key role of depression for the development of social dysfunctions, as measured by the SIS. (4) Problems were, however, acknowledged concerning the use of the SIS with severely disturbed chronic schizophrenic patients.

Plasticity is a central concept within the life-span approach of development and is defined as the ability of an individual to change and reorganize in response to environmental challenges (e.g., Baltes & Singer, 20019. Such intraindividual changes can be induced by systematic cognitive training. Recent studies suggest that substantial amounts of plasticity can be induced in executive control functions with a process-based training approach. These newer studies show that repeated practice on executive control tasks not only improved performance on these trained tasks, but also led to improvements in nontrained tasks (i.e., transfer; e.g., Jaeggi, Buschkuehl, Jonides, & Perrig, 2008; Karbach & Kray, 2009). Executive control processes are especially relevant from a developmental perspective because executive control is involved in a wide range of complex cognitive activities (e.g., van der Sluis, de Jong, & van der Leij, 2007) and is one of the most central areas of cognitive development (e.g., Craik & Bialystok, 2006). The current thesis aimed at elucidating several important questions concerning the plasticity of executive control functions induced by systematic cognitive training. Firstly, the amount, range, and stability of plasticity in adolescents and older adults were investigated. Secondly, studies explored if training design, age, and interindividual differences moderate the amount and range of plasticity. Furthermore, the current thesis aimed at exploring how process-based training specifically leads to transfer effects. To explore these questions, all studies employed a pretest-posttest-design comparing a group of participants that was trained with a process-based training approach to a group of control partici-pants that did not receive the training. Pretraining and posttraining sessions incorporated systematic assessment of transfer measures in different cognitive domains. The first study set out to investigate if executive control can be trained in adolescents with a task switching training. Additionally, the study explored what particular domains of executive control may underlie training and transfer effects, and if acute bouts of exercise directly prior to cognitive training enhance training effects. Analyses indicated substantial training effects for both training groups (with or without acute exercise) and near transfer to a similar switching task. Other findings of transfer were limited to a speed task and a tendency for faster reaction times in an updating task. Thus, findings indicate, for the first time, that executive control can be enhanced in adolescents through a short training. Furthermore, analyses suggest that updating may be of particular relevance for the effects of the task switching training. Analyses revealed no additional effects of the exercise intervention. The second study set out to explore, for the first time, the effects of a process-based training ap-proach in old-old age (above 80 years). After ten sessions of practice on working memory tasks, the training group improved in four of the five trained tasks, emphasizing the potential for plasticity even in old-old age. The gains in the training group were largely driven by individuals who started out with a low capacity in the training tasks. Thus, findings suggest that working memory can be improved with a short executive control training even in old-old age, particularly for low-capacity individuals. The absence of transfer effects in this study may point to the limits of plasticity in this age group. The third study aimed at further elucidating the mixed findings regarding the amounts of training and transfer effects induced by executive control training in older adults. For that purpose, a sample of older adults covering a wide range from young-old to old-old age (65 to 95 years) was either trained for nine sessions on a visuospatial and a verbal working memory as well as an executive control task; or served as controls. Analyses revealed significant training effects in all three trained tasks, as well as near transfer to verbal working memory and far transfer to a nonverbal reasoning task. Remarkably, all training effects and the transfer effect to verbal working memory were even stable at a nine-month follow-up. These findings suggest that cognitive plasticity is preserved over a large range of old age and that even a rather short training regimen can lead to (partly specific) training and transfer effects. However, analyses also revealed that there are a range of factors that may moderate the amount of plasticity, e.g., age and baseline performance in the training domain. To summarize, the current thesis explored effects of short executive control trainings on cognitive functions in adolescents and older adults. The findings suggest a high potential for intraindividual variability across the whole life-span. Plasticity was shown on the level of training and transfer tasks, as well as on the level of stability of effects. Furthermore, results support the notion that process-based training improves executive control processes that in turn lead to improvements in tasks that rely on these processes. The current thesis makes important contributions to the conceptual debate about the potentials and limits of training-induced plasticity across the life-span. It benefits the debate in that it specifically delineates factors that moderate the obtained effects.:Abstract ..............................................................................................1 1 General Introduction .....................................................................3 1.1 Plasticity of cognitive functions ...................................................5 1.2 Executive control functions .........................................................6 1.3 Cognitive training of executive control functions .......................9 2 Outline and Central Questions ......................................................19 2.1 What amount of plasticity does executive control training induce in different age groups? .........................................................................19 2.2 Do training and transfer effects of executive control training remain stable over time? ....................................................................20 2.3 Do training design, age, and baseline performance moderate the amount of plasticity? ...........................................................................20 2.4 Are changes in trained tasks specifically related to changes in transfer tasks? .................................................................................21 3 Study 1 - Effects of a Task Switching Training in Adolescents .......22 3.1 Introduction ..............................................................................22 3.2 Methods ....................................................................................27 3.3 Results ......................................................................................33 3.4 Discussion .................................................................................43 4 Study 2 - Effects of a Working Memory Training in Old-Old adults .48 4.1 Introduction ...............................................................................48 4.2 Methods .....................................................................................51 4.3 Results .......................................................................................54 4.4 Discussion ..................................................................................59 5 Study 3 - Factors Moderating Effects of Working Memory Training in Older Adults .......................................................................63 5.1 Introduction ................................................................................63 5.2 Methods ......................................................................................67 5.3 Results .........................................................................................71 5.4 Discussion ...................................................................................78 6 General Discussion .........................................................................83 6.1 Summary of empirical findings .....................................................83 6.2 Integration of the main empirical findings ...................................85 6.3 Conclusion and Outlook ...............................................................95 6.4 Summary ......................................................................................98 References ..........................................................................................99 Appendix ............................................................................................112

The ability to read proficiently is key to social participation and an important premise for individual well-being and vocational success. Individuals with developmental dyslexia, a highly prevalent neurodevelopmental disorder affecting hundreds of millions of children and adults worldwide, face severe and persistent difficulties in attaining adequate reading levels. Despite years of extensive research efforts to elucidate the neurobiological origin of this disorder, its exact etiology remains unclear to date. In this context, most neuroimaging research on dyslexia in humans has focused on the cerebral cortex and has identified alterations in a distributed left-lateralized cortical language network. However, pioneering post-mortem human studies and animal models suggest that dyslexia might also be associated with alterations in subcortical sensory thalami and early sensory pathways. The largely cortico-centric view of dyslexia is due in part to considerable technical challenges in assessing the human sensory thalami non-invasively using conventional magnetic resonance imaging (MRI). As a result, the role that sensory thalami may play in dyslexia has been largely unaddressed. In this dissertation, I leveraged recent advances in high-field MRI to investigate the role of the human lateral geniculate nucleus (LGN) of the visual thalamus in adults with dyslexia in-vivo. In three multi-modal high-field MRI studies, I show that (i) dyslexia is associated with structural alterations in the direct V1-bypassing white matter pathway connecting the LGN with cortical motion-sensitive area V5/MT in the left hemisphere; (ii) the connectivity strength of which predicts a core symptom of the disorder, i.e., rapid naming ability. I further demonstrate that (iii) the two major functional subdivisions of the LGN can be distinguished non-invasively based on differences in tissue microstructure; and that (iv) adults with dyslexia show functional response alterations specifically in the magnocellular subdivision of the LGN. I also demonstrate that this subdivision deficit (v) is more pronounced in male than female dyslexics; and (vi) predicts rapid naming ability in male dyslexics only. The results of this doctoral thesis are the first to confirm previous post-mortem evidence of LGN alterations in dyslexia in-vivo and point to their relevance to key symptoms of the disorder. In synergy, our research findings offer new perspectives on explanatory models of dyslexia and bear potential implications also for prospective treatment strategies.:Contribution Statement i Acknowledgments iii Abstract v Table of Contents vii 1 General Introduction 1 1.1 Developmental Dyslexia 1 1.1.1 Diagnostic Criteria 1 1.1.2 Prevalence and Etiology 2 1.1.3 Cognitive and Behavioral Symptoms 3 1.1.4 Explanatory Models in Cognitive Neuroscience 4 1.2 Lateral Geniculate Nucleus 7 1.2.1 Anatomy and Function 7 1.2.2 Technical Challenges in Conventional MRI 8 1.2.3 High-Field MRI 9 1.3 Research Aim and Chapter Outline 10 2 Altered Structural Connectivity of the Left Visual Thalamus in Developmental Dyslexia 13 2.1 Summary 14 2.2 Results and Discussion 15 2.3 Conclusions 22 2.4 Materials and Methods 23 2.4.1 Subject Details 23 2.4.2 High-Resolution MRI Acquisition and Preprocessing 23 2.4.3 Lateral Geniculate Nucleus Definition 24 2.4.4 Cortical Region of Interest Definition 26 2.4.5 Probabilistic Tractography 27 2.4.6 Quantification and Statistical Analysis 29 2.5 Supplementary Information 30 3 Mapping the Human Lateral Geniculate Nucleus and its Cytoarchitectonic Subdivisions Using Quantitative MRI 33 3.1 Abstract 34 3.2 Introduction 35 3.3 Materials and Methods 37 3.3.1 In-Vivo MRI 37 3.3.2 Post-Mortem MRI and Histology 41 3.4 Results 44 3.4.1 Lateral Geniculate Nucleus Subdivisions in In-Vivo MRI 44 3.4.2 Lateral Geniculate Nucleus Subdivisions in Post-Mortem MRI 46 3.5 Discussion 50 3.6 Supplementary Information 54 3.6.1 In-Vivo MRI 54 3.6.2 Post-Mortem MRI and Histology 58 3.6.3 Data and Code Availability 60 4 Dysfunction of the Visual Sensory Thalamus in Developmental Dyslexia 61 4.1 Abstract 62 4.2 Introduction 63 4.3 Materials and Methods 66 4.3.1 Subject Details 66 4.3.2 High-Resolution MRI Experiments 66 4.3.3 High-Resolution MRI Acquisition and Preprocessing 67 4.3.4 Lateral Geniculate Nucleus Definition 68 4.3.5 Quantification and Statistical Analysis 69 4.4 Results 70 4.5 Discussion 75 4.6 Supplementary Information 77 4.6.1 Supporting Methods 77 4.6.2 Supporting Results 81 4.6.3 Data and Code Availability 82 5 General Conclusion 83 5.1 Summary of Research Findings 83 5.2 Implications for Dyslexia Models 84 5.2.1 Phonological Deficit Hypothesis 84 5.2.2 Magnocellular Theory 84 5.2.3 Model According to Ramus 85 5.2.4 Need for Revised Model 86 5.3 Implications for Remediation 87 5.4 Research Prospects 88 5.5 Brief Concluding Remarks 90 6 Bibliography 91 7 List of Tables 113 8 List of Figures 115 9 Selbstständigkeitserklärung 117

Physical activity is positively related to cognitive functioning and brain volume in older adults. Interestingly, different types of physical activity vary in their effects on cognition and on the brain. For example, dancing has become an interesting topic in aging research, as it is a popular leisure activity among older adults, involving cardiovascular and motor fitness dimensions that can be positively related to cognition. However, studies on brain structure are missing. In this study, we tested the association of long-term senior dance experience with cognitive performance and gray matter brain volume in older women aged 65 to 82 years. We compared nonprofessional senior dancers (n=28) with nonsedentary control group participants without any dancing experience (n=29), who were similar in age, education, IQ score, lifestyle and health factors, and fitness level. Differences neither in the four tested cognitive domains (executive control, perceptual speed, episodic memory, and long-term memory) nor in brain volume (VBM whole-brain analysis, region-of-interest analysis of the hippocampus) were observed. Results indicate that moderate dancing activity (1-2 times per week, on average) has no additional effects on gray matter volume and cognitive functioning when a certain lifestyle or physical activity and fitness level are reached.